1. Field of the Invention
The present invention relates generally to motion capture, and more particularly to methods and systems for generating facial animation using performance data, such as motion capture data obtained from motion capture systems and video images obtained from video data.
2. Description of the Prior Art
Modeling a face, its motion, and rendering it in a manner that appears realistic is a difficult problem, though progress to achieve realistic looking faces has been made from a modeling perspective as well as a rendering perspective. A greater problem is animating a digital face in a realistic and believable manner that will bear close scrutiny, where slight flaws in the animated performance are often unacceptable. While adequate facial animation (stylized and realistic) can be attempted via traditional keyframe techniques by skilled animators, it is a complicated task that becomes especially time-consuming as the desired results approach realistic imagery.
Apart from keyframe techniques, other methods based on principal component analysis have also been implemented to develop animated facial models from performance data. These methods typically generate lowest-dimensional models from the data. Further, being mathematically-based solutions, the facial models so developed often look unnatural in one or more aspects. Moreover, the resulting low dimensionality makes post-development modification of the facial model difficult and non-intuitive to a user when the principal components do not correspond with natural, identifiable facial movements that can be adjusted to achieve a desired result. That is, the basis vectors (obtained using principal component analysis) do not correspond to any logical expression subset that an artist can edit afterwards. For example, a simultaneous lip corner rise with eyebrow rise might be solved from performance data as single component activation. However, the single component activation may not be decoupled into separate activations for the lip corner and eyebrow. Thus, an animator wishing to adjust only the lip corner rise may be unable to do so without also activating the eyebrow component.
Therefore, what is needed is a system and method that overcomes these significant problems found in the conventional systems as described above.